F#%^ing Toyota Celica

[80 hate]

I have a 2000 Toyota Celica GT it has 120,000 on the clock and has ran like a top for 10 years. But last week it
running rough and the check engine light came on. So I took it to auto zone to use the code reader. It said it was
an O2 sensor. So I spent $130 for a new O2 sensor and some new plugs. Well today I changed the plugs and O2 senor
and the damn thing is running like shit. It hard to start and falls on it's face when I give it gas. The check engine light is back
on and this time it is throwing a multi code... P0171 which according it auto zone is a possible 5 different things.
1. Low fuel pressure
2. Faulty MAF/VAF sensor
3. Cylinder misfire condition
4. Faulty HO2S/AF sensor
5. Large vacuum leak
I'm stuck. Does anyone have any ideas or has had this happen before?

[Flaming87lx]

A vacuum leak will cause all of those codes and symptoms, so will a weak fuel pump.... Listen for any whistling or sucking air sound under the hood and have someone check fuel pressure, u can call AZ for the fuel psi specs.... Good Luck

[8banger]

Unplug the maf and see if it runs any better.

[8banger]

Pretty sure those can be removed (2 screws)and cleaned first(maf cleaner only!).Soemtimes dust/dirt accumulate on the elements and can cause this issue.

[mustang8998]

On some cars, you need to "reset" the computer when making changes (like O2 sensor).

Might want to try that.

[80 hate]

Thanks guys...

So far I have unpluged the battery and let it set for an hour to reset the computer. I also cleaned the mass air meter. Any ideas where to take it to get fuel pressure checked? Going to start checking for vacuum leaks after dinner. Anybody have a easy way to find a vacuum leak? Also wanted to say thanks for the help. I posted this less that an hour ago.

[Kevin1989]

Thanks guys...

So far I have unpluged the battery and let it set for an hour to reset the computer. I also cleaned the mass air meter. Any ideas where to take it to get fuel pressure checked? Going to start checking for vacuum leaks after dinner. Anybody have a easy way to find a vacuum leak? Also wanted to say thanks for the help. I posted this less that an hour ago.

carb cleaner and when the car is running spray small amounts of it around vaccume lines. under intake and everywhere you can think vacuum will be. if there is infact a leak you should hear the RPMs change.

[9cobra4]

You should be able to hear a slight hissing noise, it sounds a lot like a vacuum leak to me.

[Black Horse]

I would bet on the vacuum leak. Check the lines on the backside of the motor for any melt-through.

[80 hate]

This bitch is fixed!!!!!!!!!!!!! I unpluged the MAF meter and drove it up the road. It ran alot better and started right up. So went back to auto zone and $65 later its fixed. It runs like the day I bought it.

I wanted to say thanks to all you guys who posted up. This isn't the first time this site has helped me out and if you know me it wont be the last. Get with me at QSL and Ill buy the beer.

[8banger]

This bitch is fixed!!!!!!!!!!!!! I unpluged the MAF meter and drove it up the road. It ran alot better and started right up. So went back to auto zone and $65 later its fixed. It runs like the day I bought it.

I wanted to say thanks to all you guys who posted up. This isn't the first time this site has helped me out and if you know me it wont be the last. Get with me at QSL and Ill buy the beer.

C told ya to unplug it first.:D:bigthumb Sometimes cleaning doesnt do it,but I always try that first non the less.Good deal.
glad it was only 65 bucks to replace...Some of those imports mafs are quite expensive..

[rmracing]

I just read this post but I can say that I have replaced alot of those mass airs over the years , it is very common .

[80 hate]

you called it 8banger!

[8banger]

I just read this post but I can say that I have replaced alot of those mass airs over the years , it is very common .

20 plus years here as a technician i've def seen several bad mafs.I've also seen several that had dirt,lint attached to the elements that where cleaned and good as new,specially ford mafs.Some Mafs even have the ability to heat up and clean themselves,problem is it really doesnt work all that well.lol
My usual protocol is to unplug it first see if it runs better.Unplugged most ecms/ pcms will subsitute a value based off other sensors or known calculations.if it does,I then try to clean it,that fails, I order one up.:bigthumb

[8banger]

you called it 8banger!
Just glad you got it fixed and was able to help.......:bigthumb